Adventures in associative-commutative unification

  • Authors:

  • Patrick Lincoln;Jim Christian

  • Affiliations:

  • Department of Computer Science, Stanford University, Stanford, CA, 94305, USA;Department of Computer Science, Stanford University, Stanford, CA, 94305, USA and Department of Computer Science, University of Texas at Austin, Austin, TX, 78712, USA

  • Venue:
  • Journal of Symbolic Computation
  • Year:
  • 1989

Quantified Score

Hi-index 0.00

Visualization

Abstract

We have discovered an efficient algorithm for matching and unification in associative-commutative (AC) equational theories. In most cases of AC unification our method obviates the need for solving diophantine equations, and thus avoids one of the bottlenecks of other associative-commutative unification techniques. The algorithm efficiently utilizes powerful constraints to eliminate much of the search involved in generating valid substitutions. Moreover, it is able to generate solutions lazily, enabling its use in an SLD-resolution-based environment like Prolog. We have found the method to run much faster and use less space than other associative-commutative unification procedures on many commonly encountered AC problems.